Electronics tester with output circuits operable in voltage compensated power mode, driver mode or current compensated power mode

ABSTRACT

A tester is described having output circuits that are operable in either power mode or driver mode. A switching circuit connects force and sense lines to one of the output circuits when in power mode, or connects the same lines separately to the output circuits when in driver mode. A further configuration allows for power to be provided through the lines separately while detecting a measure of power through each line and correcting for unknown resistances of leads connected to the lines.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional PatentApplication No. 62/066,276, filed on Oct. 20, 2014, all of which isincorporated herein by reference in its/their entirety.

BACKGROUND OF THE INVENTION

1) Field of the Invention

This invention relates to a tester for a device and to a method oftesting a device.

2) Discussion of Related Art

Microelectronic circuits are usually fabricated in and on semiconductorwafers. Such a wafer is subsequently “singulated” or “diced” intoindividual dies. Such a die is typically mounted to a supportingsubstrate for purposes of providing rigidity thereto and electroniccommunication with an integrated or microelectronic circuit of the die.Final packaging may include encapsulation of the die and the resultingpackage can then be shipped to a customer.

It is required that the die or the package be tested before beingshipped to a customer. Ideally, the die should be tested at an earlystage for purposes of identifying the defects that occur during earlystage manufacturing.

Such a die usually has power terminals and signal terminals. A testerusually includes a power supply and a driver circuit. Power is usuallyprovided from the power supply through a power line to the powerterminal of the die and signals such as data, clock and chip selectsignals are provided from the driver circuit through a signal line tothe signal terminals of the die.

SUMMARY OF THE INVENTION

The invention provides a tester for a device including a first outputcircuit operating as either a power circuit or a driver circuit, asecond output circuit operating as either a power circuit or a drivercircuit, first and second lines, the first line connected to an outputterminal of the first output circuit and a switching circuit operable toswitch between either a power mode or a driver mode. In the power mode(i) the first output circuit may provide power through the outputterminal of the first output circuit and the first line to a powerterminal of the device, (ii) the second line may be connectable to thepower terminal to serve as a sense line, (iii) the second line may beconnected to a feedback terminal of the first output circuit and (iv) anoutput of the second output circuit may be disconnected from the secondline. In the driver mode (i) the first output circuit may provide adriver signal through the output terminal of the first output circuitand the first line for delivery to a first signal terminal of thedevice, (ii) the second line may be disconnected from the first drivercircuit and (iii) the output of the second output circuit may beconnected to the second line to provide a driver signal through thesecond line to a second signal terminal of the device.

The tester may further include that the first output circuit may includeat least a first amplifier with an input, a reference power beingprovided to the input in the power mode, and a driver input signalprovided to the input terminal in the driver mode.

The tester may further include that the first output circuit may includeat least a second amplifier providing a different power level outputthan the first amplifier, the reference power and driver input signalbeing provided to the first and second amplifiers, the switching circuitbeing operable to select either the first amplifier or the secondamplifier.

The tester may further include a device connection resource thatincludes a holder for the device and connection leads releasablyconnecting the lines to the terminals of the device when held by theholder.

The device connection resource may be one of a probe card and a burn-inboard.

The tester may further include that the switching circuit may include afirst switch that connects the second line to the feedback terminal ofthe first output circuit and a second switch that connects the output ofthe second output circuit to the second line.

The invention also provides in a tester for a device comprising a firstoutput circuit operating as either a power circuit or a driver circuit,a second output circuit operating as either a power circuit or a drivercircuit, first and second lines, the first line connected to an outputterminal of the first output circuit, and a switching circuit, a methodof operating the switching circuit including switching the switchingcircuit between a power mode and a driver mode. In the power mode (i)the first output circuit may provide power through the output terminalof the first output circuit and the first line to a power terminal ofthe device, (ii) the second line may be connectable to the powerterminal to serve as a sense line, (iii) the second line may beconnected to a feedback terminal of the first output circuit and (iv) anoutput of the second output circuit may be disconnected from the secondline. In the driver mode, (i) the first output circuit may provide adriver signal through the output terminal of the first output circuitand the first line for delivery to a first signal terminal of thedevice, (ii) the second line may be disconnected from the first drivercircuit and (iii) the output of the second output circuit may beconnected to the second line to provide a driver signal through thesecond line to a second signal terminal of the device.

The method may further include that the first output circuit may includeat least a first amplifier with an input, a reference power beingprovided to the input in the power mode, and a driver input signalprovided to the input terminal in the driver mode.

The method may further include that the first output circuit may includeat least a second amplifier providing a different power level outputthan the first amplifier, the reference power and driver input signalbeing provided to the first and second amplifiers, the switching circuitbeing operable to select either the first amplifier or the secondamplifier.

The method may further include that the tester further includes a deviceconnection resource that includes a holder for the device and connectionleads. The method further including releasably connecting the leads tothe lines to connect the lines to the terminals.

The method may further include that the device connection resource maybe one of a probe card and a burn-in board.

The method may further include that the switching circuit may include afirst switch that connects the second line to the feedback terminal ofthe first output circuit and a second switch that connects the output ofthe second output circuit to the second line.

The invention further provides a tester for a device including a firstoutput circuit having an input and an output based on the input, a firstline connected to the output of the first output circuit, the first linehaving a first line resistance, a device connection resource thatincludes a first holder for a first device and a connection lead havinga first lead resistance and connecting the line to a first terminal onthe first device when held by the holder, a first detector detecting ameasure of power provided from the output of the first circuit to thefirst terminal of the first device and a current compensation circuitconnected to the detector and adjusting power provided to the inputbased on the measure of the power detected by the first detector.

The tester may further include a second output circuit having an inputand an output based on the input, a second line connected to the outputof the second output circuit, the second line having a second lineresistance, a device connection resource that includes a second holderfor a second device and a connection lead having a second leadresistance and connecting the line to a second terminal on the seconddevice when held by the holder, a second detector detecting a measure ofpower provided from the output of the second circuit to the secondterminal of the second device and a current compensation circuitconnected to the detector and adjusting power provided to the inputbased on the measure of the power detected by the second detector.

The tester may further include that the first lead resistance may bedifferent than the second lead resistance.

The tester may further include that the first and second leads may bereleasably connected to the first and second lines respectively.

The tester may further include that the detector may include a resistorin the first line and a voltage measurement device measuring a voltageover the first resistor.

The tester may further include that the resistance compensating circuitmay include an adder that adds an input voltage and a voltage measuredby the detector, and a multiplier that multiplies an output of the adderby a factor.

The tester may further include that the multiplier may include avariable resistor.

The invention also provides a method of testing a device includingholding the device, connecting a first lead between a first line and afirst terminal of the device, the first line having a first lineresistance and the first lead having a first lead resistance, providingan input current to a first input circuit, the first line connected toan output of the first input circuit, detecting a measure of powerprovided by the first input circuit to the first terminal; and adjustingpower provided to an input of the first input circuit based on themeasure of the power.

The method may further include connecting a second lead between a secondline and a second terminal of the device, the second line having asecond line resistance and the second lead having a second leadresistance, providing an input current to a second input circuit, thesecond line connected to an output of the second input circuit,detecting a measure of power provided by the second input circuit to thefirst terminal and adjusting power provided to an input of the secondinput circuit based on the measure of the power.

The method may further include that the first lead resistance isdifferent than the second lead resistance.

The method may further include releasably connecting the first andsecond leads to the first and second lines respectively.

The method may further include measuring a voltage over a resistor inthe first line to determine the measure of power.

The method may further include adding an input voltage and measure ofpower to obtain a sum and multiplying the sum with a factor, to adjustthe power.

The method may further include that the sum is multiplied with amultiplier having a variable resistor.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described by way of example with reference to theaccompanying drawings, wherein:

FIG. 1 is circuit diagram of components of a tester for a device whereinthe tester is configured for providing voltage compensated power;

FIG. 2 is a circuit diagram similar to FIG. 1 wherein the tester isconfigured to provide driver signal data such as i/o data, clock andchip select data;

FIG. 3 is circuit diagram similar to FIGS. 1 and 2 wherein the tester isconfigured to provide current compensated power; and

FIG. 4 is a circuit diagram of a first output circuit forming part ofthe tester.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 of the accompanying drawings illustrates a tester 10 for a device12A, including first and second output circuits 14 and 16, first andsecond lines 18 and 20, a switching circuit including first and secondswitches 22 and 24, and a device connection resource in the form of aprobe card or burn-in board 26A.

The first output circuit 14 operates as either a power circuit or adriver circuit. In FIG. 1, the first output circuit 14 operates as apower circuit. The first output circuit 14 is a first amplifier with aninput 28 connected via a switch 30 to a terminal 32. Reference power isprovided to the terminal 32.

The second output circuit 16 operates as either a power circuit or adriver circuit. The second switch 24 disconnects the second outputcircuit 16 from the second line 20. The first switch 22 connects thesecond line 20 to a feedback terminal 34 of the first output circuit 14.

The probe card or burn-in board 26A includes a holder (not shown) forthe device 12A. The device 12A is inserted into the holder before beingtested and removed from the holder after testing. The device 12A has aplurality of terminals 36A, 38A and 40A. In the present example, theterminal 36A is a power terminal. The probe card or burn-in board 26Ahas been configured so that first and second leads 42A and 44A areconnected to a terminal 46A that makes contact with the terminal 36A.The first line 18 is releasably connected to the first lead 42A viaterminals 48 and 50A. Similarly, the second line 20 is releasablyconnected to the second lead 44A via terminals 52 and 54A.

Reference power provided to the terminal 32 is amplified by the firstinput circuit 14. An output 56 of the first output circuit 14 isconnected to the first line 18. Output power provided through the output56 of the first output circuit 14 then reaches the terminal 36A of thedevice 12A via the first line 18, first lead 42A and the terminal 46A.The first line 18 and first lead 42A jointly form a force line.

A sense line is formed by the second lead 44A, second line 20 and firstswitch 22. The first output circuit 14 receives a feedback through thesense line at the feedback terminal 34. Because both force and senselines are included, very accurate voltage control can be provided to theterminal 36A of the device 12A.

FIG. 2 shows the same tester 10, but with a different probe card orburn-in card 26B than the probe card or burn-in card 26A shown inFIG. 1. Like reference numerals indicate like or similar components. Thedevice 12B has two signal terminals 38B and 40B. The first lead 42Bconnects the first line 18 to the first signal terminal 38B. The secondlead 44B connects the second line 20 to the second signal terminal 40B.The first and second output circuits 14 and 16 operate in driver mode.The first switch 22 disconnects the second line 20 from the feedbackterminal 34 of the first output circuit 14. The second switch 24connects an output 58 of the second output circuit 16 to the second line20. The outputs 56 and 58 of the first and second output circuits 14 and16 are thus connected to the first and second signal terminals 38B and40B of the device 12B, respectively.

An input 60 of the second output circuit 16 is connected to a terminal62 via a switch 64. Separate driver signals in the form of data, clock,or chip select signals are provided to the terminals 32 and 62. Thefirst and second output circuits 14 and 16 include amplifiers thatamplify the driver signals and provide the amplified driver signals viathe outputs 56 and 58 to the first and second signal terminals 38B and40B of the device 12B.

It can thus be seen that the same circuitry of the tester 10 can providepower to the power terminal 36A in FIG. 1 or to the signal terminals 38Band 40B in FIG. 2. Moreover, there is no need for increase in the numberof lines as the same lines 18 and 20 are used in the arrangements ofFIGS. 1 and 2.

The first line 18 is connected through a first comparator switch 120 toa first input terminal of a first comparator 122. A first thresholdvoltage Vth1 is applied to a second input terminal of the firstcomparator 122. An output terminal of the first comparator 122 isconnected to a first test result terminal 124. The first comparatorswitch 120 is open in FIG. 1, but closed in FIG. 2. The first comparator122 in FIG. 2 provides an output to the first test result terminal 124when the voltage on the first line is not equal to Vth1. The voltage onthe first test result terminal 124 is in proportion to the differencebetween the voltage on the first line and Vth1.

A second comparator switch 126 connects the second line 20 to a firstinput terminal of a second comparator 128. A second threshold voltageVth2 is applied to a second input terminal of the second comparator 128and an output terminal of the second comparator 128 is connected to asecond test result terminal 130. The functioning of the secondcomparator 128 is the same as the functioning of the first comparator122.

FIG. 3 illustrates a third configuration of the tester 10 with a furtherprobe card or burn-in board 26C that is different than in FIGS. 1 and 2.The probe card or burn-in board 26C includes a holder or holders for twodevices 12C and 12D. The device 12C has a power terminal 36C and thedevice 12D has a power terminal 36D. First and second leads 42C and 44Care releasably connected to the lines 18 and 20. The first switch 22 isopen so as to disconnect the second line 20 from the first outputcircuit 14. The second switch 24 is closed so that the second outputcircuit 16 is connected to the second line 20. The first line 18 has afirst line resistance (R=X). The first lead 42C has a first leadresistance (R=Z). The second line 20 has second line resistance (R=Y).The second lead 44C has a second lead resistance (R=Q). The resistancesof the first and second lines 18 and 20 are known to the manufacturer ofthe tester 10. The probe card or burn-in board 26C may be made by adifferent manufacturer and the resistances of the first and second leads42C and 44C may not be known to the manufacturer of the tester 10.

The first and second output circuits 14 and 16 are separately connectedto the power terminals 36C and 36D.

The tester 10 further includes detectors 70 and 72 and currentcompensation circuits 74 and 76. The detector 70 includes a resistor 78and an amplifier 80. The resistor 78 is located within the line 18. Theamplifier 80 measures a differential voltage over the resistor 78. Bymeasuring the differential voltage, the detector 70 thus measures thecurrent provided through the line 18, the current being a measure ofpower according to the equation P=IV=I²R=V²/R. The amplifier 80 isconnected to the current compensation circuit 74. The currentcompensation circuit 74 includes a connection switch 81, an adder 82 anda multiplier 84. The connection switch 81 is open in FIGS. 1 and 2 sothat the adder 82 is connected to ground. The connection switch 81 isclosed in FIG. 3 so that the adder 82 receives a reference voltage at aninput terminal 86. The adder 82 is connected to the amplifier 80. Theadder 82 adds the voltage measured by the amplifier 80 to the referencevoltage at the input terminal 86, to generate a sum. The multiplier 84multiplies the sum by a factor. The multiplier includes an amplifier 88and a variable resistor 90. The variable resistor 90 is set toapproximate the resistance of the first line 18. The resistance of thefirst lead 42C results in an adjustment of the reference signal providedto the input 28 of the first output circuit 14. The switch 30 is closedso that the reference signal provided by the current compensationcircuit 74 reaches the input 28 of the first output circuit 14. Shouldthe current through the first line 18 become high, the currentcompensation circuit 74 will increase the voltage, and when the currentwithin the first line 18 is low, the current compensation circuit 74decreases the voltage.

The second detector 72 has a resistor 78 and amplifier 80 similar to theresistor 78 and amplifier 80 of the detector 70. The currentcompensation circuit 76 has a connection switch 81, an adder 82 andmultiplier 84 similar to the current compensation circuit 74.

The first and second lines 18 and 20 may have different resistances.Similarly the first and second leads 42C and 44C may have differentresistances. The variable resistors 90 of the current compensationcircuits 74 and 76 may be set to different values. In addition, thedetectors 70 and 72 may detect different voltages and the currentcompensation circuits 74 and 76 may compensate for the voltages detectedby the detectors 70 and 72 to different degrees.

The configuration of FIG. 3 provides less assurance of voltage accuracythan the configuration of FIG. 1. However, in FIG. 3, the lines 18 and20 can separately provide power to terminals of devices.

As shown in FIG. 4, the first output circuit 14 includes threeamplifiers 100A, 100B and 100C in parallel. The amplifiers 100A, 100Band 100C have their outputs connected via respective switches 102A,102B, 102C, 102D and 102E and resistors 104A, 104B, 104C, 104D and 104Eto the output 56. Typically, each one of the switches 102A, 102B, 102C,102D and 102E is closed while the other switches are open. The amplifier100A is a high power amplifier that is used for providing typical power.The resistor 104A has a resistance of a particular magnitude referred toas R. The amplifier 102B is a mid-power amplifier that is typically usedfor signals. The resistor 104B has a resistivity that is approximatelyten times, shown as 10R, the resistivity of the resistor 104A. Theamplifier 100C is a low power amplifier that is typically used for aprecision measurement unit. The resistors 104C, 104D and 104E haveresistivities that scale up by a factor of 10. One or more of theresistors 104C, 104D and 104E can be selected ones of the switches 102C,102D and 102E.

The resistors 104A, 104B, 104C, 104D and 104E are used for measuringpower that is provided through the respective resistor. Suchmeasurements can be used for feedback control as described withreference to FIG. 3. Alternatively or in addition, the resistors can beused for determining a power provided and logging the power for lateranalysis.

The second output circuit 16 shown in FIGS. 1, 2 and 3 has the sameconfiguration as the first output circuit 14 shown in FIG. 4. The switch24 shown in FIGS. 1, 2 and 3 typically takes the form of one of theswitches 102A, 102B, 102C, 102D and 102E.

While certain exemplary embodiments have been described and shown in theaccompanying drawings, it is to be understood that such embodiments aremerely illustrative and not restrictive of the current invention, andthat this invention is not restricted to the specific constructions andarrangements shown and described since modifications may occur to thoseordinarily skilled in the art.

What is claimed:
 1. A tester for a device comprising: a first outputcircuit operating as either a power circuit or a driver circuit; asecond output circuit operating as either a power circuit or a drivercircuit; first and second lines, the first line connected to an outputterminal of the first output circuit; and a switching circuit operableto switch between either a power mode or a driver mode, in the powermode (i) the first output circuit providing power through the outputterminal of the first output circuit and the first line to a powerterminal of the device; (ii) the second line being connectable to thepower terminal to serve as a sense line; (iii) the second line beingconnected to a feedback terminal of the first output circuit; and (iv)an output of the second output circuit being disconnected from thesecond line, in the driver mode: (i) the first output circuit providinga driver signal through the output terminal of the first output circuitand the first line for delivery to a first signal terminal of thedevice; (ii) the second line being disconnected from the first drivercircuit; and (iii) the output of the second output circuit connected tothe second line to provide a driver signal through the second line to asecond signal terminal of the device.
 2. The tester for claim 1, whereinthe first output circuit includes at least a first amplifier with aninput, a reference power being provided to the input in the power mode,and a driver input signal provided to the input terminal in the drivermode.
 3. The tester of claim 2, wherein the first output circuitincludes at least a second amplifier providing a different power leveloutput than the first amplifier, the reference power and driver inputsignal being provided to the first and second amplifiers, the switchingcircuit being operable to select either the first amplifier or thesecond amplifier.
 4. The tester of claim 1, further comprising: a deviceconnection resource that includes: a holder for the device; andconnection leads releasably connecting the lines to the terminals of thedevice when held by the holder.
 5. The tester of claim 4, wherein thedevice connection resource is one of a probe card and a burn-in board.6. The tester of claim 1, wherein the switching circuit includes a firstswitch that connects the second line to the feedback terminal of thefirst output circuit and a second switch that connects the output of thesecond output circuit to the second line.
 7. In a tester for a devicecomprising a first output circuit operating as either a power circuit ora driver circuit, a second output circuit operating as either a powercircuit or a driver circuit, first and second lines, the first lineconnected to an output terminal of the first output circuit, and aswitching circuit, a method of operating the switching circuitcomprising: switching the switching circuit between a power mode and adriver mode, in the power mode: (i) the first output circuit providingpower through the output terminal of the first output circuit and thefirst line to a power terminal of the device; (ii) the second line beingconnectable to the power terminal to serve as a sense line; and (iii)the second line being connected to a feedback terminal of the firstoutput circuit; (iv) an output of the second output circuit beingdisconnected from the second line, in the driver mode: (i) the firstoutput circuit providing a driver signal through the output terminal ofthe first output circuit and the first line for delivery to a firstsignal terminal of the device; (ii) the second line being disconnectedfrom the first driver circuit; and (iii) the output of the second outputcircuit connected to the second line to provide a driver signal throughthe second line to a second signal terminal of the device.
 8. The methodof claim 7, wherein the first output circuit includes at least a firstamplifier with an input, a reference power being provided to the inputin the power mode, and a driver input signal provided to the inputterminal in the driver mode.
 9. The method of claim 8, wherein the firstoutput circuit includes at least a second amplifier providing adifferent power level output than the first amplifier, the referencepower and driver input signal being provided to the first and secondamplifiers, the switching circuit being operable to select either thefirst amplifier or the second amplifier.
 10. The method of claim 7,wherein the tester further comprises: a device connection resource thatincludes: a holder for the device; and connection leads, the methodfurther comprising: releasably connecting the leads to the lines toconnect the lines to the terminals.
 11. The method of claim 10, whereinthe device connection resource is one of a probe card and a burn-inboard.
 12. The tester of claim 7, wherein the switching circuit includesa first switch that connects the second line to the feedback terminal ofthe first output circuit and a second switch that connects the output ofthe second output circuit to the second line.
 13. A tester for a devicecomprising: a first output circuit having an input and an output basedon the input; a first line connected to the output of the first outputcircuit, the first line having a first line resistance; a deviceconnection resource that includes: a first holder for a first device;and a connection lead having a first lead resistance and connecting theline to a first terminal on the first device when held by the holder; afirst detector detecting a measure of power provided from the output ofthe first circuit to the first terminal of the first device; and acurrent compensation circuit connected to the detector and adjustingpower provided to the input based on the measure of the power detectedby the first detector.
 14. The tester of claim 13, further comprising: asecond output circuit having an input and an output based on the input;a second line connected to the output of the second output circuit, thesecond line having a second line resistance; a device connectionresource that includes: a second holder for a second device; and aconnection lead having a second lead resistance and connecting the lineto a second terminal on the second device when held by the holder; asecond detector detecting a measure of power provided from the output ofthe second circuit to the second terminal of the second device; and acurrent compensation circuit connected to the detector and adjustingpower provided to the input based on the measure of the power detectedby the second detector.
 15. The tester of claim 14, wherein the firstlead resistance is different than the second lead resistance.
 16. Thetester of claim 14, wherein the first and second leads are releasablyconnected to the first and second lines respectively.
 17. The tester ofclaim 13, wherein the detector includes a resistor in the first line anda voltage measurement device measuring a voltage over the firstresistor.
 18. The tester of claim 13, wherein the resistancecompensating circuit includes an adder that adds an input voltage and avoltage measured by the detector, and a multiplier that multiplies anoutput of the adder by a factor.
 19. The tester of claim 18, wherein themultiplier includes a variable resistor.
 20. A method of testing adevice comprising: holding the device; connecting a first lead between afirst line and a first terminal of the device, the first line having afirst line resistance and the first lead having a first lead resistance;providing an input current to a first input circuit, the first lineconnected to an output of the first input circuit; detecting a measureof power provided by the first input circuit to the first terminal; andadjusting power provided to an input of the first input circuit based onthe measure of the power.
 21. The method of claim 20, furthercomprising: connecting a second lead between a second line and a secondterminal of the device, the second line having a second line resistanceand the second lead having a second lead resistance; providing an inputcurrent to a second input circuit, the second line connected to anoutput of the second input circuit; detecting a measure of powerprovided by the second input circuit to the first terminal; andadjusting power provided to an input of the second input circuit basedon the measure of the power.
 22. The method of claim 21, wherein thefirst lead resistance is different than the second lead resistance. 23.The method of claim 21, further comprising: releasably connecting thefirst and second leads to the first and second lines respectively. 24.The method of claim 20, further comprising: measuring a voltage over aresistor in the first line to determine the measure of power.
 25. Themethod of claim 20, further comprising: adding an input voltage andmeasure of power to obtain a sum; and multiplying the sum with a factor,to adjust the power.
 26. The method of claim 25, wherein the sum ismultiplied with a multiplier having a variable resistor.